Bounce error fix

Outlook 550 5.7.515: domain doesn't meet authentication rules

Microsoft refused your email because your domain is missing SPF, DKIM or DMARC. Here is what it needs.

What the bounce says

550 5.7.515 Access denied, sending domain yourdomain.com does not meet the required authentication level.

Outlook.com, Hotmail and Live addresses return this when a domain sending a lot of email doesn’t have SPF, DKIM and DMARC in place. Microsoft started enforcing these sender rules on 5 May 2025.

What Microsoft asks for

SPF that passes for your sending domain.
DKIM that passes.
DMARC with at least p=none, lined up with SPF or DKIM.

How to fix it

Scan your domain with the full domain scan to see which record is missing.

Add DMARC if it’s missing. The DMARC record generator writes a safe starting record.

Fix SPF and DKIM for every service that sends as you, using the SPF checker and DKIM checker.

Resend after the changes are live. DNS updates usually show within minutes.

Check it worked

The scan shows whether you pass Gmail, Yahoo and Outlook rules in one go.